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  #61  
Old 04-24-2018, 12:50 PM
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Electronic M Electronic M is offline
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I t should be fine.... If you're still worried and have one of those TV magnifier accessories for 10/12" sets place it in front of the CRT and stand back a few feet...X Ray's are exponentially attenuated by air. Even if the CRT were a strong emitter once you get about 4 ft away the dose should be well within safe limits.

Another worry wart option would be to grab the leadded safety glass off of a color set and place it between the CRT and you.
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  #62  
Old 04-24-2018, 01:09 PM
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If there wuz anything to the Xray scare, all my kids should have two heads and six fingers.

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  #63  
Old 04-24-2018, 05:28 PM
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25kv is starting to produce X-rays, and unlike color CRTs, that one most likely does not contain enough lead or thickness to reduce them. As said above, standing back several feet should be good enough protection. Also, X-ray effects are cumulative, so if you just have a quick look to see the shape of the circle, no problem. As an additional measure, you can turn down the brightness and run at much lower beam current for direct viewing.
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  #64  
Old 04-24-2018, 05:47 PM
WISCOJIM WISCOJIM is online now
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What about trying to view the CRT image in the reflection of a regular mirror. Can you get one in position to do that?

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  #65  
Old 04-24-2018, 06:13 PM
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Quote:
Originally Posted by WISCOJIM View Post
What about trying to view the CRT image in the reflection of a regular mirror. Can you get one in position to do that?

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X rays do not beam straight out the front. They spread in all directions.
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  #66  
Old 04-24-2018, 09:22 PM
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Quote:
Originally Posted by old_tv_nut View Post
X rays do not beam straight out the front. They spread in all directions.
I was thinking of giving him an angle to see inside, such as using a hand mirror.

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  #67  
Old 04-24-2018, 10:35 PM
EdKozk2 EdKozk2 is offline
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Hi Phil,
Your picture of the egg shaped vertical test pattern reminded me of the issue I had with my Stewart Warner 9100 mirror lid set. In order to correct it in my case I made a change to the RC time constant in the plate circuit of the vertical blocking oscillator. The original per Sams' was a 0.15mfd cap and a 2200 ohm resistor. I ended up using a 0.1mfd and 330 ohm resistor to get a balanced ellipse vertically. Increasing the width adjustment then made the the image circular.
You made great progress.
Ed

Last edited by EdKozk2; 04-27-2018 at 01:34 AM. Reason: typo
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  #68  
Old 04-26-2018, 07:22 PM
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Quote:
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If you go back to page 1 of this thread, you'll see that I removed a one-capacitor modification made by a previous owner: that cap paralleled the width coil and the idea seems to have been to affect the width. Now I'm tempted to reinstall a cap in that position and see what happens . . . .
Well, putting a cap (something from .33 to .66) across the width coil increases the width and lets you adjust for somewhat better horizontal linearity.

For comparison, here's the previous test pattern:



And here's today's pattern:



Not a great improvement, but something. It still feels like the horizontal circuits are just "off" in general -- the adjusters for horiz drive, horiz linearity, and horiz size are all maxed in one direction.

The worst horizontal linearity is not at the far left edge, but in a band that starts maybe 20% in from the left edge. If you squeezed that band horizontally, you'd have a pretty watchable picture.

Strangely, now it's easier to adjust for better vertical linearity.

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  #69  
Old 04-27-2018, 04:03 PM
kvflyer kvflyer is offline
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Have you ruled out optics and are now focused (pun intended) on the sweep circuits? I know that you were reluctant to view the face of the actual CRT.
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  #70  
Old 04-27-2018, 08:42 PM
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Kindof a slow evening, and this thread caught my attention....

" Not a great improvement, but something. It still feels like the horizontal circuits are
just "off" in general -- the adjusters for horiz drive, horiz linearity, and horiz size are
all maxed in one direction. "

I wonder, Could you post a picture however bad it may look with all those knobs
set at mid-point...?

Another goofy thought..... Is there any chance that the metal housing with all
that optics has been magnetized...?

I guess a quick answer might come if you looked at the picture outside all
that optics..... But then I did read about your worry of x-rays....

With both H and V off in linearity, are the V lin and V height also maxed in one
direction ?

Seems like a voltage rail common to both H and V would be a good place to look.

Looks like that will be a neat tv !


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Last edited by Username1; 04-27-2018 at 08:48 PM.
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  #71  
Old 04-27-2018, 10:03 PM
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I decided not to mess with the optics until I have more faith in the electronics. Looking back at my notes, I saw several components still unchecked in the vertical & sync circuits. Plus, I want to check voltages in the sync & sweep circuits. The Sams manual doesn't show any oscilloscope waveforms, but the Riders manual includes a few, so scoping is also on the list.

Time to finish my homework, in other words, before I look for more exotic causes.

The first resistor I checked today was a 3W dogbone style. It's spec'd at 10K and it measured at 24K (!). At first glance, you might think it's wirewound, but this just looks like a fat carbon rod with leads attached to the ends. Way out of spec, anyhow.

I believe the vertical linearity control was also maxed. Not vertical size, though.

Hope to spend more time on this over the weekend.

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  #72  
Old 05-02-2018, 07:43 PM
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Josef Josef is offline
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I'd reverse the vertical and horizontal deflection wires and see what happens. If the pattern is mirrowed the defect comes from the electronics, if it stays the same the optics are faulty
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  #73  
Old 05-02-2018, 09:15 PM
Tom9589 Tom9589 is offline
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I don't think that will work as the horizontal and vertical yoke windings are quite different in resistance and inductance.
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  #74  
Old 05-02-2018, 09:42 PM
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I thought Josef meant swapping the horizontal wires (pins 5 & 7 in the schematic) with each other and then swapping the vertical wires (pins 2 & 6) with each other. (In other words, not swapping the pair of horizontal wires with the pair of vertical wires.) Or am I misreading one or both of you?

Phil Nelson

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  #75  
Old 05-02-2018, 10:23 PM
EdKozk2 EdKozk2 is offline
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Hi Phil,
Just reversing the two horizontal wire connections within the same circuit is what makes sense. The same would go for the vertical connections. One thing to watch for is if the picture is reversed. Lettering or words on the final viewed image will be incorrect. Just like putting a slide in a slide projector backwards.
Ed
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